Disc polarimeters can be used to measure organic substances with optical rotation. The disk polarimeter can be used to measure the specific gravity, purity, concentration and content of active substances (such as sugar solution, turpentine oil or camphor). This polarimeter with ergonomic design and simple operation. The 589nm sodium lamp is used as the optimal light source for linearly polarized light. The scale graduation of 1° with vernier (0.05°) enables exact determination of the angle of rotation of the substance to be examined. Two sizes of glass cuvettes are included of100 mm and 200 mm for various samples sizes. The built-in LED light considerably extends the service life of the lamp.